Let's see if I have this straight.
By "my crush" do you mean you have a thing for him or he has a thing for you ? I'll assume the former.
You squeeze past a group of guys, one of whom is someone you like, and they stop talking when you say, "Excuse me." Hardly surprising, they're probably gobsmacked you didn't say "please", but that aside, at school age, when a member of the opposite sex talks to you, it's a big deal. Clearly they all found you more interesting that whatever they were chatting about.
Then a second male friend starts singing ?!?!? Does he do that often ? Was this in class, or in the library ? Well never mind, let's skip that bit.
And this guy you are keen on has a friend who then says, "That's your competition." So he's saying the singing guy is gay or bi and fancies the guy that you fancy ?
It all seems rather strange to me. Perhaps best to give them all a wide berth.